Answer:
Step-by-step explanation:
This is an equation for which you need to solve for the value of the missing angle beta.
sin(15) has a decimal answer that you will find on your calculator. Finding that value makes this equation then
cosβ = .2588190451
Now use the 2nd button and then the cos button to find the angle that has a cos of that decimal. When you hit 2nd then cos, you should see this on your screen:
cos⁻¹ (
After that open parenthesis, enter you decimal then hit the enter button to find the angle. You should get 75, which is Choice B.